In wireless charging systems, wireless power transmitting devices transmit power wirelessly to wireless power receiving devices. In some configurations, wireless power transmitting devices such as wireless charging mats are able to transmit power wirelessly to a variety of different wireless power receiving devices. The wireless power receiving devices each have rectifier circuitry for receiving wireless alternating-current (AC) power from the wireless charging mat. The rectifier circuitry is used in converting the received AC power into direct-current (DC) power.